Skyline carriage

ABSTRACT

A pair of opposed sheaves are mounted towards the top of the skyline carriage, such that the carriage can move along a suspended skyline cable. Extending through the carriage beneath the pair of sheaves is a haul-back cable, one end of which runs to a yarding drum while the other end is connected to the mainline cable. The mainline cable runs from the mainline yarding drum through the carriage and over a sheave within the carriage that allows the bottom portion of the mainline to extend downwardly toward the ground. A clamping system within the carriage and actuated through tension control on the cables acts to clamp and release the skyline cable and the haul-back cable, depending on the mode of operation desired.

United States Patent 1191 3,863,774 Brandt Feb. 4, 1975 SKYLINE CARRIAGE Primary Examiner-Robert J. Spar [75] Inventor: Dennis L. Brandt, Broken Bow, Amman Exammer R'- Johnson Okla. [73] Assignee: Weyerhaeuser Company, Tacoma, [57] ABSTRACT w h A pair of opposed sheaves are mounted towards the top of the skyline carriage, such that the carriage can [22] Flled' 1974 move along a suspended skyline cable. Extending [2]] A l N 452,022 through the carriage beneath the pair of sheaves is a haul-back cable, one end of which runs to a yarding drum while the other end is connected to the mainline [52] 1.8. Cl. 212/94, 212/122 cable The mainline cable runs from the mainline [51] hit. Cl. B66C 21/00 yarding drum through the carriage and Over a sheave [58] held of Search 212/94 122 within the carriage that allows the bottom portion of the mainline to extend downwardly toward the [56] References cued ground. A clamping system within the carriage and ac- UNITED S ATES PATENTS tuated through tension control on the cables acts to 2,601,228 6/1952 Shields 212/122 clamp and release the skyline cable and the haul-back 3,079,008 2/1963 Naud cable, depending on the mode of operation desired. 3,336,878 8/1967 Malakhofi 212/94 3 Claims, 3 Drawing Figures fams le PATENTED EB 4191s SHEET 3 OF 3 SKYLINE CARRIAGE BACKGROUND OF THE INVENTION This invention relates generally to skyline carriages and more particularly to a skyline carriage that is useful for logging operations where safety, simplicity, and efficiency is desired.

There are many known skyline carriages and skyline logging systems that carry out the function of moving a turn of logs from one point to another. The systems are similar and generally have a skyline carriage that traverses thelogging area on a skyline cable by proper actuation of a haul-back cable that essentially controls the position of the carriage on the skyline cable. The mainline cable extends downwardly through the carriage and has a grapple device on the end so as to grasp the logs. Some examples of known skyline carriages and skyline logging systems may be seen by referring to the following issuedUS'Pat. Nos.: McIntyre et al. Re. 27,621, Lysons et al. 3,718,262, Rennie et al. 3,712,478, Larsen 3,011,653, Naud 2,685,373, Whitlock 1,725,325, Fayette 1,543,373, Ball 1,164,628, ODell 428,349 and Day 419,004. While the skyline carriages and logging systems disclosed in the above cited prior art patents offer various apparatus and methods for moving logs or the like from one point to another, none is particularly adapted to smaller loads and with the improved safety features as in the skyline carriage of the present invention. Another advantage with the skyline carriage of the present invention is that it is less costly to manufacture and operate, compared to most of those of the prior art.

Among the advantages of the present invention are that the skyline carriage depends from a fixed skyline cable as opposed to a running skyline cable. A positive clamping arrangement is provided internal to the carriage and acts to positively clamp the carriage to the skyline at the point where logs are to be picked up and conversely the carriage is positively clamped to the haul-back cable when the carriage is either returned to the landing or returned to the point of log collection.

From the foregoing, one object of the present invention is to provide a skyline carriage tht is simple in design yet efficient in operation. Another object of the invention is to provide a skyline carriage for use in logging operations that has improved safety features over prior art carriages. Yet another object is to provide a skyline carriage that is lightweight and inexpensive to fabricate. These and other objects of the invention will become apparent upon reading the following specification in conjunction with the attached drawing.

SUMMARY OF THE INVENTION Briefly stated, this inventionis practiced in one form by suspending a skyline carriage from a fixed skyline cable and also having the haul-back cable and mainline cable operatively extending through the carriage. The haul-back cable is spliced or otherwise connected to a point on the mainline cable at a position on the yarder BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a graphic depiction of the skyline carriage of the present invention within its operating environment.

FIG. 2 is a section view taken through the skyline carriage showing the internal mechanism within the carriage in a position where it is locked on the skyline cable.

FIG. 3 is a view similar to FIG. 2, only showing the internal locking mechanism in a position where the carriage is locked to the haul-back cable.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, a typical skyline logging system is depicted and includes a yarder generally indicated at 2, a skyline carriage indicated generally at 4, and a spar pole generally indicated at 6. Of course, as will be recognized by those skilled in the art, since the logging system is of the overhead type, the spar pole 6 and the yarder mast 8 will generally be well above the ground level, since the grappling of logs normally takes place at ground level as is depicted in FIG. 1.

The yarder 2 disclosed in FIG. 1 is of the type mounted on wheels 10 and therefore is adapted to move from place to place, depending on the area to be logged. Also included at the front of yarder 2 is the haul-back yarding drum 12 and the mainline yarding drum 14. Both drums l2, 14 are powered and are adapted to rotate independently of each other. Extending between the top of the yarder mast 8 and a high position on spar pole 6 is the skyline cable 16. Cable 16 is fixed relative to mast 8 and spar pole 6 and can be fixed to the spar pole 6 through any suitable attaching means, such as through a clamping loop arrangement. At the yarder mast 8 the skyline cable 16 can extend rearwardly of the yarder 2 and be affixed at a ground point so as to give additional support to yarder 2 and skyline cable 16. Similarly, one or more cables 18 can be extended downwardly to ground from the spar pole 6 in order to give additional support to the overall skyline logging system.

Also at the top of yarder mast 8 are a pair of independently rotatable pulleys, the top one of which is indicated at 20 supports the mainline cable 22, while the bottom pulley indicated at 24 supports the haul-back cable indicated at 26. The mainline and haul-back cables 22, 26 are comprised of different functionally and operationally related portions which will now be described in order to have a full understanding of the present invention. One portion of mainline cable 22 is that extending from the mainline yarding drum 14 to the top pulley 20 and is indicated as section 220. The portion of the mainline cable extending from pulley 20 to the skyline carriage 4 is indicated as section 22b and the portion of mainline 22 extending downwardly from skyline carriage 4 is indicated as section 22c. Section 22c extends downwardly from carriage 4 to a mainline clamp 28 which is fixed to the mainline cable. The final section 22d of mainline cable 22 is that extending from the mainline clamp 28 to the grapple attachment 30 which is fixed to the free end of mainline cable 22. The grapple attachment 30 may be of any suitable variety operable for the intended function of grasping an object such as log 31.

Similar to mainline cable 22, the haul-back cable 26 has a plurality of relatd sections. The section extending from the haul-back yarding drum 12 to the bottom pulley 24 on the mast 8 is indicated as section 26a. The portion of the haul-back cable extending between the bottom pulley 24 outwardly to a position in close proximity to the spar pole 6 is indicated as section 26b. At this position, the haul-back cable 26 reverses itself and extends back toward the skyline carriage 4, such portion of which is indicated as section 26c. In the embodiment as depicted in FIG. 1, the reversal arrangement for the haul-back cable 26 is comprised of a pair of vertically spaced pulleys 32 and 34. Pulley 34 is shown mounted on a stump 36 which is, of course, fixed to the ground. The top pulley 32 is fixed at a position on the spar pole 6 which is in close proximity to the position where the skyline cable 16 is attached thereto. The final portion of haul-back cable 26 is that indicated as section 26d and is that section which extends through the carriage 4 and outwardly a distance toward the yarder 2 to a position where it is fixably connected at connection point 38 to the mainline cable 22.

SKYLINE CARRIAGE STRUCTURE Turning now more specifically to the structure of the skyline carriage, reference will be made to FIGS. 2 and 3. Looking first at FIG. 2, the structure depicted would be for a condition as that depicted in FIG. 1 where the grapple attachment 30 and mainline cable section 22d is below the carriage 4. In this mode of operation the skyline carriage 4 will be fixed to the skyline cable 16 while the haul-back and mainline cables 22, 26 will be free to move through the carriage 4.

The basic structure for skyline carriage 4 is similar to those known to the art in that a pair of spaced sheaves or grooved wheels 40, 42 are positioned within the carriage 4 and towards the top thereof so as to run on skyline cable 16. Each of the sheaves 40, 42 are rotatable about respective axles- 46, 48. The carriage body 44 then depends downwardly from the pair of sheaves 40, 42 and generally below the skyline cable 16. Positioned at the bottom the carriage body 44 is a cylindrically shaped channel 50 through which the mainline cable 22 passes after it changes from the horizontal plane to a vertical plane by passing over a rotatable mainline sheave or grooved pulley 52 which rotates on an axle 54. As previously mentioned, the connection point 38 where the end of haul-back cable 26 at its section 26dis fixed to the mainline cable 22, at an axial position which is generally, during operation, on the yarder side of the mainline sheave 52. It should be noted that since the two cables are connected at point 38, the haul-back cable section 26d and mainline cable section 22b will generally be along the same axis prior to the mainline cable passing over the sheave 52 and then becoming section 22c.

In order to carry out the intended function ofthe skyline yarding system, two cooperating locking mechanisms are provided internal to the carriage body 44, one being the skyline clamping mechanism generally indicated at 56 and the other being the haul-back clamping mechanism generally indicated at 58. A cooperating linkage mechanism generally indicated at 60 operates to control each of the clamps depending on the tensioning of the mainline cable and the haul-back cable as set by the operator within yarder 2. During operation, one of the respective clamping mechanisms will be locked while the other will be unlocked, allowing the carriage to either be fixed or movable on the skyline cable 16.

There are several skyline clamping mechanisms that are known in the art, one in particular being that disclosed in the Whitlock US. Pat. No. 1,725,325. The skyline clamping mechanism 56 of the present invention is comprised of a flat stationary shoe member 62 and a vertically movable clamping plate 64. When the clamping plate 64 is in its uppermost position, it clamps and holds the carriage 4 from moving on the skyline cable. Positioned on the spar pole side of the carriage body 44 and in line with the haul-back cable 26 is haulback clamping mechanism 58 which similarly is comprised of a flat stationary shoe member 66 and a vertically movable clamping plate 68. A similar kind of locking action occurs at the haul-back clamping mechanism 58 as does at the skyline clamping mechanism 56. In the clamping mechanism 56 a suitably sized skyline clamping spring 70 is provided to force the clamping plate 64 upwardly to its clamping plate 64 upwardly to its clamping or locked relationship against the skyline cable 16. The spring 70 exerts its biasing force against a spring tensioning nut 71 which is threadably mounted on a skyline clamp drive rod 72. Drive rod 72 is attached at one end to the clamping plate 64 through the pinned connection 73 while at the other end it is slidably mounted in skyline spring stop 77 which in turn is fixed to the carriage body 44 through any suitable means such as welding. The haul-back and skyline clamping mechanisms 56, 58 are operatively connected to a linkage mechanism 60. Describing the linkage mechanism 60 first and then the clamping mechanisms 56, 58 it is seen that mechanism 60 is comprised of a generally vertically extending linking shaft 76. At the upper end of linking shaft 76 is a pivotal connection point 78 and at the bottom end of linking shaft 76 is a flat plate member 80, which is adapted to be slidably mounted within the cylindrical channel 50. A suitable aperture 81 is provided in the plate member such that the mainline cable 22 is freely movable through the carriage body 44. At pivotal connection 78 a lever arm extends outwardly from linking shaft 76 and upwardly toward the clamping plate 64 and is indicated at 82. Lever arm 82 is in turn pivotal about a fixed point 84 approximately midway between its respective ends. At the other end of lever arm 82 is a pivotal connection 86 which connects to the clamping plate 64 at the same point as does the pinned connection 73 of drive rod 72. A stabilizing linking arm 88 can be appropriately positioned at the other end of the clamping plate 64 in order to stabilize the vertical movement of the plate 64. A stop 90 is positioned below and toward one end of the lever arm 82 and acts to halt the downward movement of the linking shaft 76. Similarly, another stop 92 is appropriately positioned so as to halt the movement of linking arm 88 when it moves vertically downward. A pair of vertically spaced stabilizing pins 91 act to constrain the movement of shaft 76 by way of the vertical slide way 93 within shaft 76.

Turning now to a description of the haul-back clamping mechanism 58, it is apparent from the figures that it is controlled through movement of the linking shaft 76. Fixed to shaft 76 toward the bottom thereof is an outwardly extending arm 94 which in turn has a pin 95 extending transverse to it at its outer end. The pin is adapted to fit within an aperture 96 that is formed in a rotatable member 97. The aperture 96 is positioned toward the top of member 97 and has a plurality of surfaces that allow the pin 95 to slide thereabout upon movement of shaft 76. Since member 97 is rotatable about a fixed point indicated at 98, it will be appreciated that when the linking shaft 76 moves a sufficient distance up or down, the pin 95 will hit its corresponding stop point within aperture 96 and thereby cause member 97 to'rotate about point 98.

Fixed to the bottom of member 97 and extending downwardly therefrom is a dog member 99 that has a turnbuckle 100 attached to its outer end through a pinned connection 101. Of course, it will be appreciated that when member 97 is caused to rotate, it in turn will cause dog 99 to move the turnbuckle 100 either to the left or right transversely to shaft 76.

The motion of the turnbuckle 100 is transformed into a vertical movement of the clamping plate 68 through a pivotal linkage arm 103. Linkage arm 103 is pivotal about fixed point 104 with an upper portion 105 extending upwardly toward plate 68 and attached thereto at a pinned connection point 106. The lower portion line cable and this in turn will cause the linking shaft 76 to move vertically upward, thereby unlocking the skyline clamping mechanism 56. At the same time, the arm 103 will be caused to rotate about pivot point 104 thereby forcing the clamping plate 68 against the haulback cable 26 and locking the haul-back clamping mechanism 58. Of course, it will be appreciated that while the operator is winding in the mainline cable 22, he is at the same time reeling out the haul-back yarding drum 12.

107 of arm 103- extends downwardly from pivot point 104 to the end of turnbuckle 100 where it is attached thereto through the pinned connection 108. It is seen in FIGS. 2 and 3 that the two portions of linkage arm 103 are both ata slight angle from the vertical direction. By constructing the haul-back clamping mechanism 58 in such a manner it will be recognized that upward movement of shaft 76 will act to move clamping plate 68 upward against haul-back cable 26 thereby locking the carriage 44 to cable 26. Providing a stabilizing and equalizing function to allow clamping plate 68 to move up and down uniformly is a pivoting arm 108a attached at one an h qushpinnes qnnest amlm one end of plate 68 and at the other end to a fixed pinned connection -108(:.

Providing additional biasing means for haul-back clamping mechanism58 when in the locked position is the haul-back biasing spring 109. Spring 109 acts to exert additional side force against the lower portion 107 of arm 103 which in turn acts to exert the upward force against the clamping plate 68. A linking arrangement acts to transfer the spring force to the arm 103 and is comprised of an arm 110 pivotal about fixed point 111 to which is connected at its upper end the biasing arm 112 through a pinned connection 113. Biasing arm 112 is then attached at its other end through pinned connection 114 to the arm 103. At the other end of arm 110 is a pinned connection 115 which connects the haul-back biasing drive rod 116 to arm 110 for transmittal of the spring force to arm 103.1Spring 109 extends between a lower stop 117 and a spring tensioning nut 118 in a manner similar to that of spring 70. In order for the spring 109 to carry out its intended function its strength will be less than that of spring 70.

A pair of vertically spaced guiding pins 102 can be provided in order to positively constrain the vertical movement of haul-back cable portion 26d within the carriage body 44. The guiding pins 102 also provide a positive constraint to prevent the connection 38 between the haul-back cable and mainline cable from passing beyond the mainline sheave 52.

OPERATION OF THE INVENTION Starting with a normal sequence of operations, it will be assumed that the skyline carriage 4 is at a position At this point the skyline carriage 4 is free to move along the skyline cable 16. Sufficient tension is maintained on mainline cable 22 while at the same time the haul-back yarding drum 12 is caused to pull the carriage 4 along the skyline cable 16. When the carriage 4 is in the proper position over the logging area, the tension on the mainline cable 22 is relaxed and mainline cable 22 is allowed to pass through the carriage 4 over the sheave 52 at which point an operator at ground level will secure the grapple attachment 30 and fix it to the logs to be moved. Once the tension is released on mainline cable 22, the mainline clamp 28 will begin to move downwardly and in response to this movement, the linking shaft 76 will also start to move vertically downward due to the force exerted by the skyline clamping spring 70. Upon the downward movement of the linking shaft 76, the clamping plate 64 will move upwardly and against the skyline cable 16. At this point, the skyline clamping mechanism 56 is locked and since the arm 103 has pivoted about point 104 causing the clamping plate 68 to move downwardly, the haul-back clamping mechanism 58 will be unlocked. Since the haul-back clamping mechanism 58 is now in the unlocked position as the mainline cable 22 is allowed to move downwardly to ground level, the haulback cable can be reeled in to pick up the slack on yarding drum 12. This sequence of operations allows the grapple attachment 30 to grasp its load while the skyline carriage 4 is securely locked to the skyline cable 16 overhead. Since the haul-back cable 26 is being reeled in while mainline cable is being reeled out, the jointly operating cables are kept in proper tension.

The operator now is ready to bring the logs into the yarder 2. At this point, the mainline yarding drum 14 will begin to apply tension and reel in the mainline cable 22. The haul-backyarding drum 12 is reversed. As section 22d of the mainline cable is moved vertically upward, the mainline clamp 28 will ultimately reach the downwardly extended plate member and since the operator continues to apply tension through the mainline yarding drum 14, the clamp 28 will cause the linking shaft 76 to move upward, thereby releasing the skyline clamping mechanism 56 and locking the haulback clamping mechanism 58. With the load and skyline carriage in this position, the operator then continues to reel in the mainline 'cable 22 while reeling out haul-back cable 26. This function is, of course, possible since the haul-back cable is connected to the mainline cable at connection point 38 on the yarder side of the carriage 4. After the skyline carriage 4 traverses the proper distance on skyline cable 16 and the load is at the proper position, the mainline yarding drum 14 will begin to reel out mainline cable 22, releasing the haulback clamping mechanism 58 and locking the skyline clamping mechanism 56. When a suitable amount of mainline cable has been allowed to move downwardly through the skyline carriage 4, a ground operator will release the grapple attachment 30 from the load and the sequence of operations will be repeated.

While a detailed example of the principal embodiment has been described, it is understood that many I changes and modifications may be made in the above described skyline carriage and logging system without departing from the spirit of the invention. All such modifications are intended to be included within the scope of the appended claims.

What is claimed is:

l. A skyline carriage of the type with first and second sides and a bottom adapted to traverse a skyline cable and having mainline and haulback cables in operative communication therewith together with means to independently actuate said mainline and haulback cables with the improvement comprising:

means within the carriage to direct the mainline cale from its entry point at the first side of said carriage to the bottom thereof such that a portion of said mainline cable extends downwardly from the bottom of said carriage,

means to direct the haulback cable from its entry point at the second side of said carriage toward said first side,

means to join the end of said haulback cable to said mainline cable at a position which is above said mainline cable directing means and generally in the same plane therewith, and

a locking mechanism for sequentially locking and unlocking said carriage to said skyline cable and to said haul-back cable comprising:

means to sense a vertical position of the downwardly extending portion of said mainline cable,

first means responsive to said sensing means to lock the carriage to the hualback cable and to substantially simultaneously unlock the carriage from said skyline cable when the downwardly extending portion of the mainline cable is substantially in its uppermost position, and

second means responsive to said sensing means to lock the carriage to the skyline cable and to substantially simultaneously unlock the carriage from said haulback cable when the downwardly extending portion of the mainline cable is in a lower vertical position with respect to its uppermost position.

2. The skyline carriage as in claim 1 in which the sensing means is comprised of a clamp fixed to said mainline cable at a position at the beginning of said downwardly extending portion and a vertically moveable plate member positioned at the bottom of said carriage.

3. The skyline carriage as in claim 2 in which said first and second means is comprised of haulback and skyline clamping mechanisms in operative communication with each other through a linkage mechanism which are adapted to open and close respectively depending on the position of said clamp.

" UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO- ,774 Dated February 4, 1975 Inventor(s) DENNIS BRANDT It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In column 1, line 44, "tht" should read "that";

in column 3, line 2 "relatd" should read '-related-; in column 4, line 21, delete second "plate 64 upwardly";

in column 4, line 22, delete "to its clamping"; I in column 6, line 16, between "haulback" and "yarding" insert --cable 26 on haul-back";

in column 8, line 9, I "hualback" should read -haulback--; and

in column 7, line 24', "cale" should read '--cabl'e'--.

Signed and sealed this 29th day of April 1975.

(SEAL).

Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks 

1. A skyline carriage of the type with first and second sides and a bottom adapted to traverse a skyline cable and having mainline and haulback cables in operative communication therewith together with means to independently actuate said mainline and haulback cables with the improvement comprising: means within the carriage to direct the mainline cale from its entry point at the first side of said carriage to the bottom thereof such that a portion of said mainline cable extends downwardly from the bottom of said carriage, means to direct the haulback cable from its entry point at the second side of said carriage toward said first side, means to join the end of said haulback cable to said mainline cable at a position which is above said mainline cable directing means and generally in the same plane therewith, and a locking mechanism for sequentially locking and unlocking said carriage to said skyline cable and to said haul-back cable comprising: means to sense a vertical position of the downwardly extending portion of said mainline cable, first means responsive to said sensing means to lock the carriage to the hualback cable and to substantially simultaneously unlock the carriage fRom said skyline cable when the downwardly extending portion of the mainline cable is substantially in its uppermost position, and second means responsive to said sensing means to lock the carriage to the skyline cable and to substantially simultaneously unlock the carriage from said haulback cable when the downwardly extending portion of the mainline cable is in a lower vertical position with respect to its uppermost position.
 2. The skyline carriage as in claim 1 in which the sensing means is comprised of a clamp fixed to said mainline cable at a position at the beginning of said downwardly extending portion and a vertically moveable plate member positioned at the bottom of said carriage.
 3. The skyline carriage as in claim 2 in which said first and second means is comprised of haulback and skyline clamping mechanisms in operative communication with each other through a linkage mechanism which are adapted to open and close respectively depending on the position of said clamp. 